（一）数据库的基本操作
一、创建库
1.最简单数据库创建
[root@MySQL ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.31 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> SHOW DATABASES; #查看现有数据库
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| mytest |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.05 sec)
mysql> CREATE DATABASE test1; #创建数据库
Query OK, 1 row affected (0.00 sec)
mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| mytest |
| performance_schema |
| sys |
| test1 |
+--------------------+
6 rows in set (0.00 sec)
mysql>
2.数据库创建的语法
mysql> help create #查看与create相关的命令
Many help items for your request exist.
To make a more specific request, please type 'help <item>',
where <item> is one of the following
topics:
CREATE DATABASE
CREATE EVENT
CREATE FUNCTION
CREATE FUNCTION UDF
CREATE INDEX
CREATE LOGFILE GROUP
CREATE PROCEDURE
CREATE SCHEMA
CREATE SERVER
CREATE TABLE
CREATE TABLESPACE
CREATE TRIGGER
CREATE USER
CREATE VIEW
SHOW
SHOW CREATE DATABASE
SHOW CREATE EVENT
SHOW CREATE FUNCTION
SHOW CREATE PROCEDURE
SHOW CREATE SCHEMA
SHOW CREATE TABLE
SHOW CREATE USER
SPATIAL INDEXES
mysql>
mysql> help create database; #查看与创建数据库相关的语法
Name: 'CREATE DATABASE'
Description:
Syntax:
CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name
[create_option] ...
#DATABASE与SCHEMA的作用相同，IF NOT EXISTS表示“即如果不存在”，是创建数据库时判断该数据库是否存在的，不存在创建新的，存在不创建
create_option: {
[DEFAULT] CHARACTER SET [=] charset_name #设置字符集
| [DEFAULT] COLLATE [=] collation_name #设置校验集
}
CREATE DATABASE creates a database with the given name. To use this
statement, you need the CREATE privilege for the database. CREATE
SCHEMA is a synonym for CREATE DATABASE.
URL: https://dev.mysql.com/doc/refman/5.7/en/create-database.html
mysql>
3.if not exists（即如果不存在）的作用
mysql> create schema mytest; #对于已经存在的数据库报error错误，且不能创建
ERROR 1007 (HY000): Can't create database 'mytest'; database exists
mysql>
mysql> create schema if not exists mytest; #对于已经存在的数据库能创建，但提示warning
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> show databases; #对于已经存在的数据库并没创建新的，旧的仍然存在
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| mytest |
| performance_schema |
| sys |
| test1 |
+--------------------+
6 rows in set (0.00 sec)
mysql> use mytest; #切换数据库
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables; #之前创建的表仍然存在
+------------------+
| Tables_in_mytest |
+------------------+
| test |
+------------------+
1 rows in set (0.00 sec)
mysql> create database if not exists mytest; #database与schema的作用相同
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql>
4.show命令的使用
语法
mysql> help show; #需要使用show命令
Name: 'SHOW'
Description:
SHOW has many forms that provide information about databases, tables,
columns, or status information about the server. This section describes
those following:
SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW CHARACTER SET [like_or_where]
SHOW COLLATION [like_or_where]
SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
SHOW CREATE DATABASE db_name #显示已经创建的库
SHOW CREATE EVENT event_name
SHOW CREATE FUNCTION func_name
SHOW CREATE PROCEDURE proc_name
SHOW CREATE TABLE tbl_name
SHOW CREATE TRIGGER trigger_name
SHOW CREATE VIEW view_name
SHOW DATABASES [like_or_where]
SHOW ENGINE engine_name {STATUS | MUTEX}
SHOW [STORAGE] ENGINES
SHOW ERRORS [LIMIT [offset,] row_count]
SHOW EVENTS
SHOW FUNCTION CODE func_name
SHOW FUNCTION STATUS [like_or_where]
SHOW GRANTS FOR user
SHOW INDEX FROM tbl_name [FROM db_name]
SHOW MASTER STATUS
SHOW OPEN TABLES [FROM db_name] [like_or_where]
SHOW PLUGINS
SHOW PROCEDURE CODE proc_name
SHOW PROCEDURE STATUS [like_or_where]
SHOW PRIVILEGES
SHOW [FULL] PROCESSLIST
SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]
SHOW PROFILES
SHOW RELAYLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW SLAVE HOSTS
SHOW SLAVE STATUS [FOR CHANNEL channel]
SHOW [GLOBAL | SESSION] STATUS [like_or_where]
SHOW TABLE STATUS [FROM db_name] [like_or_where]
SHOW [FULL] TABLES [FROM db_name] [like_or_where]
SHOW TRIGGERS [FROM db_name] [like_or_where]
SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
SHOW WARNINGS [LIMIT [offset,] row_count]
like_or_where: {
LIKE 'pattern'
| WHERE expr
}
If the syntax for a given SHOW statement includes a LIKE 'pattern'
part, 'pattern' is a string that can contain the SQL % and _ wildcard
characters. The pattern is useful for restricting statement output to
matching values.
Several SHOW statements also accept a WHERE clause that provides more
flexibility in specifying which rows to display. See
https://dev.mysql.com/doc/refman/5.7/en/extended-show.html.
URL: https://dev.mysql.com/doc/refman/5.7/en/show.html
mysql>
5.字符集的使用
（1）查看所有的字符集
mysql> SHOW CHARACTER SET; #查看字符集
+----------+---------------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+---------------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| utf16le | UTF-16LE Unicode | utf16le_general_ci | 4 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
| gb18030 | China National Standard GB18030 | gb18030_chinese_ci | 4 |
+----------+---------------------------------+---------------------+--------+
41 rows in set (0.00 sec)
mysql>
（2）使用字符集创建数据库
mysql> create database test2 default character set = gb2312; #字符集为gb2312
Query OK, 1 row affected (0.00 sec)
mysql>
6.SHOW CREATE DATABASE db_name（显示已经创建的库）
（1）语法
mysql> help SHOW DATABASES;
Name: 'SHOW DATABASES'
Description:
Syntax:
SHOW {DATABASES | SCHEMAS}
[LIKE 'pattern' | WHERE expr]
SHOW DATABASES lists the databases on the MySQL server host. SHOW
SCHEMAS is a synonym for SHOW DATABASES. The LIKE clause, if present,
indicates which database names to match. The WHERE clause can be given
to select rows using more general conditions, as discussed in
https://dev.mysql.com/doc/refman/5.7/en/extended-show.html.
You see only those databases for which you have some kind of privilege,
unless you have the global SHOW DATABASES privilege. You can also get
this list using the mysqlshow command.
If the server was started with the --skip-show-database option, you
cannot use this statement at all unless you have the SHOW DATABASES
privilege.
MySQL implements databases as directories in the data directory, so
this statement simply lists directories in that location. However, the
output may include names of directories that do not correspond to
actual databases.
Database information is also available from the INFORMATION_SCHEMA
SCHEMATA table. See
https://dev.mysql.com/doc/refman/5.7/en/schemata-table.html.
*Caution*:
Because a global privilege is considered a privilege for all databases,
any global privilege enables a user to see all database names with SHOW
DATABASES or by examining the INFORMATION_SCHEMA SCHEMATA table.
URL: https://dev.mysql.com/doc/refman/5.7/en/show-databases.html
mysql>
（2）使用
mysql> SHOW CREATE DATABASE test2;
+----------+------------------------------------------------------------------+
| Database | Create Database |
+----------+------------------------------------------------------------------+
| test2 | CREATE DATABASE `test2` /*!40100 DEFAULT CHARACTER SET gb2312 */ |
+----------+------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>
7.校验集的使用
（1）查看所有的校验集
mysql> SHOW COLLATION;
+--------------------------+----------+-----+---------+----------+---------+
| Collation | Charset | Id | Default | Compiled | Sortlen |
+--------------------------+----------+-----+---------+----------+---------+
| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 |
| big5_bin | big5 | 84 | | Yes | 1 |
| dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 |
| dec8_bin | dec8 | 69 | | Yes | 1 |
| cp850_general_ci | cp850 | 4 | Yes | Yes | 1 |
| cp850_bin | cp850 | 80 | | Yes | 1 |
| hp8_english_ci | hp8 | 6 | Yes | Yes | 1 |
| hp8_bin | hp8 | 72 | | Yes | 1 |
| koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 |
| koi8r_bin | koi8r | 74 | | Yes | 1 |
| latin1_german1_ci | latin1 | 5 | | Yes | 1 |
| latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 |
| latin1_danish_ci | latin1 | 15 | | Yes | 1 |
| latin1_german2_ci | latin1 | 31 | | Yes | 2 |
| latin1_bin | latin1 | 47 | | Yes | 1 |
| latin1_general_ci | latin1 | 48 | | Yes | 1 |
| latin1_general_cs | latin1 | 49 | | Yes | 1 |
| latin1_spanish_ci | latin1 | 94 | | Yes | 1 |
| latin2_czech_cs | latin2 | 2 | | Yes | 4 |
| latin2_general_ci | latin2 | 9 | Yes | Yes | 1 |
| latin2_hungarian_ci | latin2 | 21 | | Yes | 1 |
| latin2_croatian_ci | latin2 | 27 | | Yes | 1 |
| latin2_bin | latin2 | 77 | | Yes | 1 |
| swe7_swedish_ci | swe7 | 10 | Yes | Yes | 1 |
| swe7_bin | swe7 | 82 | | Yes | 1 |
| ascii_general_ci | ascii | 11 | Yes | Yes | 1 |
| ascii_bin | ascii | 65 | | Yes | 1 |
| ujis_japanese_ci | ujis | 12 | Yes | Yes | 1 |
| ujis_bin | ujis | 91 | | Yes | 1 |
| sjis_japanese_ci | sjis | 13 | Yes | Yes | 1 |
| sjis_bin | sjis | 88 | | Yes | 1 |
| hebrew_general_ci | hebrew | 16 | Yes | Yes | 1 |
| hebrew_bin | hebrew | 71 | | Yes | 1 |
| tis620_thai_ci | tis620 | 18 | Yes | Yes | 4 |
| tis620_bin | tis620 | 89 | | Yes | 1 |
| euckr_korean_ci | euckr | 19 | Yes | Yes | 1 |
| euckr_bin | euckr | 85 | | Yes | 1 |
| koi8u_general_ci | koi8u | 22 | Yes | Yes | 1 |
| koi8u_bin | koi8u | 75 | | Yes | 1 |
| gb2312_chinese_ci | gb2312 | 24 | Yes | Yes | 1 |
| gb2312_bin | gb2312 | 86 | | Yes | 1 |
| greek_general_ci | greek | 25 | Yes | Yes | 1 |
| greek_bin | greek | 70 | | Yes | 1 |
| cp1250_general_ci | cp1250 | 26 | Yes | Yes | 1 |
| cp1250_czech_cs | cp1250 | 34 | | Yes | 2 |
| cp1250_croatian_ci | cp1250 | 44 | | Yes | 1 |
| cp1250_bin | cp1250 | 66 | | Yes | 1 |
| cp1250_polish_ci | cp1250 | 99 | | Yes | 1 |
| gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 |
| gbk_bin | gbk | 87 | | Yes | 1 |
| latin5_turkish_ci | latin5 | 30 | Yes | Yes | 1 |
| latin5_bin | latin5 | 78 | | Yes | 1 |
| armscii8_general_ci | armscii8 | 32 | Yes | Yes | 1 |
| armscii8_bin | armscii8 | 64 | | Yes | 1 |
| utf8_general_ci | utf8 | 33 | Yes | Yes | 1 |
| utf8_bin | utf8 | 83 | | Yes | 1 |
| utf8_unicode_ci | utf8 | 192 | | Yes | 8 |
| utf8_icelandic_ci | utf8 | 193 | | Yes | 8 |
| utf8_latvian_ci | utf8 | 194 | | Yes | 8 |
| utf8_romanian_ci | utf8 | 195 | | Yes | 8 |
| utf8_slovenian_ci | utf8 | 196 | | Yes | 8 |
| utf8_polish_ci | utf8 | 197 | | Yes | 8 |
| utf8_estonian_ci | utf8 | 198 | | Yes | 8 |
| utf8_spanish_ci | utf8 | 199 | | Yes | 8 |
| utf8_swedish_ci | utf8 | 200 | | Yes | 8 |
| utf8_turkish_ci | utf8 | 201 | | Yes | 8 |
| utf8_czech_ci | utf8 | 202 | | Yes | 8 |
| utf8_danish_ci | utf8 | 203 | | Yes | 8 |
| utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 |
| utf8_slovak_ci | utf8 | 205 | | Yes | 8 |
| utf8_spanish2_ci | utf8 | 206 | | Yes | 8 |
| utf8_roman_ci | utf8 | 207 | | Yes | 8 |
| utf8_persian_ci | utf8 | 208 | | Yes | 8 |
| utf8_esperanto_ci | utf8 | 209 | | Yes | 8 |
| utf8_hungarian_ci | utf8 | 210 | | Yes | 8 |
| utf8_sinhala_ci | utf8 | 211 | | Yes | 8 |
| utf8_german2_ci | utf8 | 212 | | Yes | 8 |
| utf8_croatian_ci | utf8 | 213 | | Yes | 8 |
| utf8_unicode_520_ci | utf8 | 214 | | Yes | 8 |
| utf8_vietnamese_ci | utf8 | 215 | | Yes | 8 |
| utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 |
| ucs2_general_ci | ucs2 | 35 | Yes | Yes | 1 |
| ucs2_bin | ucs2 | 90 | | Yes | 1 |
| ucs2_unicode_ci | ucs2 | 128 | | Yes | 8 |
| ucs2_icelandic_ci | ucs2 | 129 | | Yes | 8 |
| ucs2_latvian_ci | ucs2 | 130 | | Yes | 8 |
| ucs2_romanian_ci | ucs2 | 131 | | Yes | 8 |
| ucs2_slovenian_ci | ucs2 | 132 | | Yes | 8 |
| ucs2_polish_ci | ucs2 | 133 | | Yes | 8 |
| ucs2_estonian_ci | ucs2 | 134 | | Yes | 8 |
| ucs2_spanish_ci | ucs2 | 135 | | Yes | 8 |
| ucs2_swedish_ci | ucs2 | 136 | | Yes | 8 |
| ucs2_turkish_ci | ucs2 | 137 | | Yes | 8 |
| ucs2_czech_ci | ucs2 | 138 | | Yes | 8 |
| ucs2_danish_ci | ucs2 | 139 | | Yes | 8 |
| ucs2_lithuanian_ci | ucs2 | 140 | | Yes | 8 |
| ucs2_slovak_ci | ucs2 | 141 | | Yes | 8 |
| ucs2_spanish2_ci | ucs2 | 142 | | Yes | 8 |
| ucs2_roman_ci | ucs2 | 143 | | Yes | 8 |
| ucs2_persian_ci | ucs2 | 144 | | Yes | 8 |
| ucs2_esperanto_ci | ucs2 | 145 | | Yes | 8 |
| ucs2_hungarian_ci | ucs2 | 146 | | Yes | 8 |
| ucs2_sinhala_ci | ucs2 | 147 | | Yes | 8 |
| ucs2_german2_ci | ucs2 | 148 | | Yes | 8 |
| ucs2_croatian_ci | ucs2 | 149 | | Yes | 8 |
| ucs2_unicode_520_ci | ucs2 | 150 | | Yes | 8 |
| ucs2_vietnamese_ci | ucs2 | 151 | | Yes | 8 |
| ucs2_general_mysql500_ci | ucs2 | 159 | | Yes | 1 |
| cp866_general_ci | cp866 | 36 | Yes | Yes | 1 |
| cp866_bin | cp866 | 68 | | Yes | 1 |
| keybcs2_general_ci | keybcs2 | 37 | Yes | Yes | 1 |
| keybcs2_bin | keybcs2 | 73 | | Yes | 1 |
| macce_general_ci | macce | 38 | Yes | Yes | 1 |
| macce_bin | macce | 43 | | Yes | 1 |
| macroman_general_ci | macroman | 39 | Yes | Yes | 1 |
| macroman_bin | macroman | 53 | | Yes | 1 |
| cp852_general_ci | cp852 | 40 | Yes | Yes | 1 |
| cp852_bin | cp852 | 81 | | Yes | 1 |
| latin7_estonian_cs | latin7 | 20 | | Yes | 1 |
| latin7_general_ci | latin7 | 41 | Yes | Yes | 1 |
| latin7_general_cs | latin7 | 42 | | Yes | 1 |
| latin7_bin | latin7 | 79 | | Yes | 1 |
| utf8mb4_general_ci | utf8mb4 | 45 | Yes | Yes | 1 |
| utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 |
| utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 |
| utf8mb4_icelandic_ci | utf8mb4 | 225 | | Yes | 8 |
| utf8mb4_latvian_ci | utf8mb4 | 226 | | Yes | 8 |
| utf8mb4_romanian_ci | utf8mb4 | 227 | | Yes | 8 |
| utf8mb4_slovenian_ci | utf8mb4 | 228 | | Yes | 8 |
| utf8mb4_polish_ci | utf8mb4 | 229 | | Yes | 8 |
| utf8mb4_estonian_ci | utf8mb4 | 230 | | Yes | 8 |
| utf8mb4_spanish_ci | utf8mb4 | 231 | | Yes | 8 |
| utf8mb4_swedish_ci | utf8mb4 | 232 | | Yes | 8 |
| utf8mb4_turkish_ci | utf8mb4 | 233 | | Yes | 8 |
| utf8mb4_czech_ci | utf8mb4 | 234 | | Yes | 8 |
| utf8mb4_danish_ci | utf8mb4 | 235 | | Yes | 8 |
| utf8mb4_lithuanian_ci | utf8mb4 | 236 | | Yes | 8 |
| utf8mb4_slovak_ci | utf8mb4 | 237 | | Yes | 8 |
| utf8mb4_spanish2_ci | utf8mb4 | 238 | | Yes | 8 |
| utf8mb4_roman_ci | utf8mb4 | 239 | | Yes | 8 |
| utf8mb4_persian_ci | utf8mb4 | 240 | | Yes | 8 |
| utf8mb4_esperanto_ci | utf8mb4 | 241 | | Yes | 8 |
| utf8mb4_hungarian_ci | utf8mb4 | 242 | | Yes | 8 |
| utf8mb4_sinhala_ci | utf8mb4 | 243 | | Yes | 8 |
| utf8mb4_german2_ci | utf8mb4 | 244 | | Yes | 8 |
| utf8mb4_croatian_ci | utf8mb4 | 245 | | Yes | 8 |
| utf8mb4_unicode_520_ci | utf8mb4 | 246 | | Yes | 8 |
| utf8mb4_vietnamese_ci | utf8mb4 | 247 | | Yes | 8 |
| cp1251_bulgarian_ci | cp1251 | 14 | | Yes | 1 |
| cp1251_ukrainian_ci | cp1251 | 23 | | Yes | 1 |
| cp1251_bin | cp1251 | 50 | | Yes | 1 |
| cp1251_general_ci | cp1251 | 51 | Yes | Yes | 1 |
| cp1251_general_cs | cp1251 | 52 | | Yes | 1 |
| utf16_general_ci | utf16 | 54 | Yes | Yes | 1 |
| utf16_bin | utf16 | 55 | | Yes | 1 |
| utf16_unicode_ci | utf16 | 101 | | Yes | 8 |
| utf16_icelandic_ci | utf16 | 102 | | Yes | 8 |
| utf16_latvian_ci | utf16 | 103 | | Yes | 8 |
| utf16_romanian_ci | utf16 | 104 | | Yes | 8 |
| utf16_slovenian_ci | utf16 | 105 | | Yes | 8 |
| utf16_polish_ci | utf16 | 106 | | Yes | 8 |
| utf16_estonian_ci | utf16 | 107 | | Yes | 8 |
| utf16_spanish_ci | utf16 | 108 | | Yes | 8 |
| utf16_swedish_ci | utf16 | 109 | | Yes | 8 |
| utf16_turkish_ci | utf16 | 110 | | Yes | 8 |
| utf16_czech_ci | utf16 | 111 | | Yes | 8 |
| utf16_danish_ci | utf16 | 112 | | Yes | 8 |
| utf16_lithuanian_ci | utf16 | 113 | | Yes | 8 |
| utf16_slovak_ci | utf16 | 114 | | Yes | 8 |
| utf16_spanish2_ci | utf16 | 115 | | Yes | 8 |
| utf16_roman_ci | utf16 | 116 | | Yes | 8 |
| utf16_persian_ci | utf16 | 117 | | Yes | 8 |
| utf16_esperanto_ci | utf16 | 118 | | Yes | 8 |
| utf16_hungarian_ci | utf16 | 119 | | Yes | 8 |
| utf16_sinhala_ci | utf16 | 120 | | Yes | 8 |
| utf16_german2_ci | utf16 | 121 | | Yes | 8 |
| utf16_croatian_ci | utf16 | 122 | | Yes | 8 |
| utf16_unicode_520_ci | utf16 | 123 | | Yes | 8 |
| utf16_vietnamese_ci | utf16 | 124 | | Yes | 8 |
| utf16le_general_ci | utf16le | 56 | Yes | Yes | 1 |
| utf16le_bin | utf16le | 62 | | Yes | 1 |
| cp1256_general_ci | cp1256 | 57 | Yes | Yes | 1 |
| cp1256_bin | cp1256 | 67 | | Yes | 1 |
| cp1257_lithuanian_ci | cp1257 | 29 | | Yes | 1 |
| cp1257_bin | cp1257 | 58 | | Yes | 1 |
| cp1257_general_ci | cp1257 | 59 | Yes | Yes | 1 |
| utf32_general_ci | utf32 | 60 | Yes | Yes | 1 |
| utf32_bin | utf32 | 61 | | Yes | 1 |
| utf32_unicode_ci | utf32 | 160 | | Yes | 8 |
| utf32_icelandic_ci | utf32 | 161 | | Yes | 8 |
| utf32_latvian_ci | utf32 | 162 | | Yes | 8 |
| utf32_romanian_ci | utf32 | 163 | | Yes | 8 |
| utf32_slovenian_ci | utf32 | 164 | | Yes | 8 |
| utf32_polish_ci | utf32 | 165 | | Yes | 8 |
| utf32_estonian_ci | utf32 | 166 | | Yes | 8 |
| utf32_spanish_ci | utf32 | 167 | | Yes | 8 |
| utf32_swedish_ci | utf32 | 168 | | Yes | 8 |
| utf32_turkish_ci | utf32 | 169 | | Yes | 8 |
| utf32_czech_ci | utf32 | 170 | | Yes | 8 |
| utf32_danish_ci | utf32 | 171 | | Yes | 8 |
| utf32_lithuanian_ci | utf32 | 172 | | Yes | 8 |
| utf32_slovak_ci | utf32 | 173 | | Yes | 8 |
| utf32_spanish2_ci | utf32 | 174 | | Yes | 8 |
| utf32_roman_ci | utf32 | 175 | | Yes | 8 |
| utf32_persian_ci | utf32 | 176 | | Yes | 8 |
| utf32_esperanto_ci | utf32 | 177 | | Yes | 8 |
| utf32_hungarian_ci | utf32 | 178 | | Yes | 8 |
| utf32_sinhala_ci | utf32 | 179 | | Yes | 8 |
| utf32_german2_ci | utf32 | 180 | | Yes | 8 |
| utf32_croatian_ci | utf32 | 181 | | Yes | 8 |
| utf32_unicode_520_ci | utf32 | 182 | | Yes | 8 |
| utf32_vietnamese_ci | utf32 | 183 | | Yes | 8 |
| binary | binary | 63 | Yes | Yes | 1 |
| geostd8_general_ci | geostd8 | 92 | Yes | Yes | 1 |
| geostd8_bin | geostd8 | 93 | | Yes | 1 |
| cp932_japanese_ci | cp932 | 95 | Yes | Yes | 1 |
| cp932_bin | cp932 | 96 | | Yes | 1 |
| eucjpms_japanese_ci | eucjpms | 97 | Yes | Yes | 1 |
| eucjpms_bin | eucjpms | 98 | | Yes | 1 |
| gb18030_chinese_ci | gb18030 | 248 | Yes | Yes | 2 |
| gb18030_bin | gb18030 | 249 | | Yes | 1 |
| gb18030_unicode_520_ci | gb18030 | 250 | | Yes | 8 |
+--------------------------+----------+-----+---------+----------+---------+
222 rows in set (0.00 sec)
mysql> mysql> SHOW COLLATION like '%utf8%'; #筛选带utf8的校验集
+--------------------------+---------+-----+---------+----------+---------+
| Collation | Charset | Id | Default | Compiled | Sortlen |
+--------------------------+---------+-----+---------+----------+---------+
| utf8_general_ci | utf8 | 33 | Yes | Yes | 1 |
| utf8_bin | utf8 | 83 | | Yes | 1 |
| utf8_unicode_ci | utf8 | 192 | | Yes | 8 |
| utf8_icelandic_ci | utf8 | 193 | | Yes | 8 |
| utf8_latvian_ci | utf8 | 194 | | Yes | 8 |
| utf8_romanian_ci | utf8 | 195 | | Yes | 8 |
| utf8_slovenian_ci | utf8 | 196 | | Yes | 8 |
| utf8_polish_ci | utf8 | 197 | | Yes | 8 |
| utf8_estonian_ci | utf8 | 198 | | Yes | 8 |
| utf8_spanish_ci | utf8 | 199 | | Yes | 8 |
| utf8_swedish_ci | utf8 | 200 | | Yes | 8 |
| utf8_turkish_ci | utf8 | 201 | | Yes | 8 |
| utf8_czech_ci | utf8 | 202 | | Yes | 8 |
| utf8_danish_ci | utf8 | 203 | | Yes | 8 |
| utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 |
| utf8_slovak_ci | utf8 | 205 | | Yes | 8 |
| utf8_spanish2_ci | utf8 | 206 | | Yes | 8 |
| utf8_roman_ci | utf8 | 207 | | Yes | 8 |
| utf8_persian_ci | utf8 | 208 | | Yes | 8 |
| utf8_esperanto_ci | utf8 | 209 | | Yes | 8 |
| utf8_hungarian_ci | utf8 | 210 | | Yes | 8 |
| utf8_sinhala_ci | utf8 | 211 | | Yes | 8 |
| utf8_german2_ci | utf8 | 212 | | Yes | 8 |
| utf8_croatian_ci | utf8 | 213 | | Yes | 8 |
| utf8_unicode_520_ci | utf8 | 214 | | Yes | 8 |
| utf8_vietnamese_ci | utf8 | 215 | | Yes | 8 |
| utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 |
| utf8mb4_general_ci | utf8mb4 | 45 | Yes | Yes | 1 |
| utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 |
| utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 |
| utf8mb4_icelandic_ci | utf8mb4 | 225 | | Yes | 8 |
| utf8mb4_latvian_ci | utf8mb4 | 226 | | Yes | 8 |
| utf8mb4_romanian_ci | utf8mb4 | 227 | | Yes | 8 |
| utf8mb4_slovenian_ci | utf8mb4 | 228 | | Yes | 8 |
| utf8mb4_polish_ci | utf8mb4 | 229 | | Yes | 8 |
| utf8mb4_estonian_ci | utf8mb4 | 230 | | Yes | 8 |
| utf8mb4_spanish_ci | utf8mb4 | 231 | | Yes | 8 |
| utf8mb4_swedish_ci | utf8mb4 | 232 | | Yes | 8 |
| utf8mb4_turkish_ci | utf8mb4 | 233 | | Yes | 8 |
| utf8mb4_czech_ci | utf8mb4 | 234 | | Yes | 8 |
| utf8mb4_danish_ci | utf8mb4 | 235 | | Yes | 8 |
| utf8mb4_lithuanian_ci | utf8mb4 | 236 | | Yes | 8 |
| utf8mb4_slovak_ci | utf8mb4 | 237 | | Yes | 8 |
| utf8mb4_spanish2_ci | utf8mb4 | 238 | | Yes | 8 |
| utf8mb4_roman_ci | utf8mb4 | 239 | | Yes | 8 |
| utf8mb4_persian_ci | utf8mb4 | 240 | | Yes | 8 |
| utf8mb4_esperanto_ci | utf8mb4 | 241 | | Yes | 8 |
| utf8mb4_hungarian_ci | utf8mb4 | 242 | | Yes | 8 |
| utf8mb4_sinhala_ci | utf8mb4 | 243 | | Yes | 8 |
| utf8mb4_german2_ci | utf8mb4 | 244 | | Yes | 8 |
| utf8mb4_croatian_ci | utf8mb4 | 245 | | Yes | 8 |
| utf8mb4_unicode_520_ci | utf8mb4 | 246 | | Yes | 8 |
| utf8mb4_vietnamese_ci | utf8mb4 | 247 | | Yes | 8 |
+--------------------------+---------+-----+---------+----------+---------+
53 rows in set (0.00 sec)
mysql> SHOW COLLATION where Charset = 'utf8'; #只筛选utf8的校验集
+--------------------------+---------+-----+---------+----------+---------+
| Collation | Charset | Id | Default | Compiled | Sortlen |
+--------------------------+---------+-----+---------+----------+---------+
| utf8_general_ci | utf8 | 33 | Yes | Yes | 1 |
| utf8_bin | utf8 | 83 | | Yes | 1 |
| utf8_unicode_ci | utf8 | 192 | | Yes | 8 |
| utf8_icelandic_ci | utf8 | 193 | | Yes | 8 |
| utf8_latvian_ci | utf8 | 194 | | Yes | 8 |
| utf8_romanian_ci | utf8 | 195 | | Yes | 8 |
| utf8_slovenian_ci | utf8 | 196 | | Yes | 8 |
| utf8_polish_ci | utf8 | 197 | | Yes | 8 |
| utf8_estonian_ci | utf8 | 198 | | Yes | 8 |
| utf8_spanish_ci | utf8 | 199 | | Yes | 8 |
| utf8_swedish_ci | utf8 | 200 | | Yes | 8 |
| utf8_turkish_ci | utf8 | 201 | | Yes | 8 |
| utf8_czech_ci | utf8 | 202 | | Yes | 8 |
| utf8_danish_ci | utf8 | 203 | | Yes | 8 |
| utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 |
| utf8_slovak_ci | utf8 | 205 | | Yes | 8 |
| utf8_spanish2_ci | utf8 | 206 | | Yes | 8 |
| utf8_roman_ci | utf8 | 207 | | Yes | 8 |
| utf8_persian_ci | utf8 | 208 | | Yes | 8 |
| utf8_esperanto_ci | utf8 | 209 | | Yes | 8 |
| utf8_hungarian_ci | utf8 | 210 | | Yes | 8 |
| utf8_sinhala_ci | utf8 | 211 | | Yes | 8 |
| utf8_german2_ci | utf8 | 212 | | Yes | 8 |
| utf8_croatian_ci | utf8 | 213 | | Yes | 8 |
| utf8_unicode_520_ci | utf8 | 214 | | Yes | 8 |
| utf8_vietnamese_ci | utf8 | 215 | | Yes | 8 |
| utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 |
+--------------------------+---------+-----+---------+----------+---------+
27 rows in set (0.00 sec)
mysql>
（2）使用字符集创建数据库
mysql> create database if not exists test5 default character set = utf8 default collate = utf8_icelandic_ci;
Query OK, 1 row affected (0.02 sec)
mysql> show create database test5;
+----------+------------------------------------------------------------------------------------------+
| Database | Create Database |
+----------+------------------------------------------------------------------------------------------+
| test5 | CREATE DATABASE `test5` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_icelandic_ci */ |
+----------+------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql>
二、删除数据库
1.语法
mysql> help drop;
Many help items for your request exist.
To make a more specific request, please type 'help <item>',
where <item> is one of the following
topics:
ALTER TABLE
ALTER TABLESPACE
DEALLOCATE PREPARE
DROP DATABASE
DROP EVENT
DROP FUNCTION
DROP FUNCTION UDF
DROP INDEX
DROP PREPARE
DROP PROCEDURE
DROP SCHEMA
DROP SERVER
DROP TABLE
DROP TABLESPACE
DROP TRIGGER
DROP USER
DROP VIEW
mysql> help DROP DATABASE;
Name: 'DROP DATABASE'
Description:
Syntax:
DROP {DATABASE | SCHEMA} [IF EXISTS] db_name
DROP DATABASE drops all tables in the database and deletes the
database. Be very careful with this statement! To use DROP DATABASE,
you need the DROP privilege on the database. DROP SCHEMA is a synonym
for DROP DATABASE.
*Important*:
When a database is dropped, privileges granted specifically for the
database are not automatically dropped. They must be dropped manually.
See [HELP GRANT].
IF EXISTS is used to prevent an error from occurring if the database
does not exist.
URL: https://dev.mysql.com/doc/refman/5.7/en/drop-database.html
mysql>
2.应用
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| mytest |
| performance_schema |
| sys |
| test1 |
| test2 |
| test5 |
+--------------------+
8 rows in set (0.00 sec)
mysql> drop schema test5; #删除数据库方法一
Query OK, 0 rows affected (0.04 sec)
mysql> drop database test1; #删除数据库方法二
Query OK, 0 rows affected (0.00 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| mytest |
| performance_schema |
| sys |
| test2 |
+--------------------+
6 rows in set (0.00 sec)
mysql> drop database test1; #删除不存在的数据库
ERROR 1008 (HY000): Can't drop database 'test1'; database doesn't exist
mysql> drop database if exists test1; #添加if exists参数删除不存在的数据库
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql>
这只是我的一些浅薄的见解，望多指教！
